[Scip] branching on constraints

Ambros Gleixner gleixner at zib.de
Mon Apr 8 23:50:02 MEST 2013


Dear Alessia,

constraint-based branching is rather straightforward to implement in 
SCIP.  You have to add a new branching rule that uses the methods 
SCIPcreateChild() and SCIPaddConsNode() in its branching callbacks.

A very good example for this is the Ryan/Foster branching rule that has 
been implemented in the binpacking example:

http://scip.zib.de/doc/examples/Binpacking/index.shtml

http://scip.zib.de/doc/examples/Binpacking/branch__ryanfoster_8c_source.shtml


Hope that helps,

Ambros



Am 08.04.2013 15:47, schrieb Alessia Violin:
> Hello,
>
> solving my problem with branch&price I would like to change the
> branching. Now I am branching on binary variables x_a^k = sum_j l_a^j *
> x_a^k,j <= 1, simply defining them as binary in the variable definition
> as they do not occur in the pricing. The variables for the pricing are
> l_a^j, and x_a^k,j are parameters that I calculate during the pricing.
>
> As those x_a^k variables are added only for the branching, I would like
> to eliminate them and branch directly on constraints sum_a l_a^j *
> x_a^k,j <=1 (they can be 0 or 1).
>
> Does it exist already in SCIP a branching rule on constraints? If not,
> shall I do it defining a new branching rule or is there an easier way to
> do it?
>
> Thank you in advance for any help and suggestion,
>
> Alessia
>


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